Immunostimulating carrier for vaccines

Abstract: A polymer that has utility as immunostimulating carrier is a copolymer of ethylene pipe razing N-oxide and N-(carboxymethyl)ethylene-piperazinium.

Description: Field of the Invention This invention relates to an immunostimulating carrier for vaccines. Background of the Invention Helminthic infections are a major cause of morbidity and mortality in both domesticated animals and human populations. Speaking generally, helminths refer to parasitic and non-parasitic species belonging to the phyla platyhelminthes (for example, flukes, tapeworms, and other flatworms) and nematahelminthes (for example, roundworms and their relatives). The following is illustrative of how helminthic infections occur. A helminth species enters the body of a host in the form of eggs or invasive larvae, for example, as a result of the ingestion by the host organism of food containing the eggs or larvae. The helminths then develop, moving slowly through different tissues, blood and/or lymph. Finally, they reach their "preferred" organ, and grow and mature. Eventually, the organ in which they reside is affected adversely. Control measures rely to a large extent on improvements in hygiene, reduction in vector populations, and chemotherapy. Control measures which focus on hygiene and reduction of vector population have proved to be problematic especially in developing countries where such infections are most prevalent and such control measures are most difficult to implement. Current chemotherapeutic medications all have drawbacks such as high toxicity, the requirement that treatments be repeated and immunosuppressive side-effects. Furthermore, the use of these preparations often results in the parasites' developing resistance to the chemotherapeutic medication. Indeed, nearly every country has documented cases of antihelminthic resistance. For these reasons, as well as the expense of repeated administration of chemotherapeutic compounds, a compound which would not have these drawbacks has been highly sought after. Since a large variety of helminth species may be found in infected populations, it would desirable to produce a vaccine having a broad spectrum of prophylactic activity. To date, the induction of strong protective host immunity following infection by helminths has been uncommon. The long co-evolutionary experience these parasites have had with their hosts has driven the host-parasite relationship to a level of accommodation that results in chronic or persistent conditions rather than acute infections that typically yield strong specific immunity. For this reason, unlike the situation with most microbial diseases of animals, few vaccines have been available for helminth control, and those which do exist have significant drawbacks. Of the known methods of producing helminth vaccines, inactivated and living vaccines have the drawback that they are labor-intensive and only weakly immunogenic and they induce side-effects such as a localized inflammation, allergic response, and fever. Furthermore, often the attenuated form used in the vaccine causes a disease similar to that induced by the virulent (wild) forms of the parasite. In addition, the macromolecular carrier proteins used in these vaccine preparations cause a number of immunopathologic side-effects in the vaccinated organism. The other available class of vaccines comprises genetically engineered antigens. Yet these too are only weakly immunogenic. In summary, the available types of vaccines are generally ineffective and possess a narrow specificity, being directed against a single parasite. Reported Developments A detailed description of helminths in whose life-cycles tissue-migration plays an important part, as well as a discussion of the pathological conditions they cause can be found for example in E.J. Soulsby, Helminth , Arthropods and Protozoa of Domesticated Animals, 7th Edition, Lea and Febiger, Philadelphia (1982) and in G.M. Urquhart, "Veterinary Parasitology", Longman Scientific and Technical, United Kingdom (1987). All parasites elicit immune responses, but for many reasons are able to present a moving and sometimes invisible target to the host's immune response, to such an extent that the normal control mechanisms fail and immunological damage instead of immunity often occurs. This in turn frequently leads the host to switch off its ineffective and often counterproductive immune response, thereby resulting in gross pathological changes and immunosuppression. The structural and antigenic diversity of the parasitic helminths is reflected in the heterogeneity of the specific immune responses they elicit. Parasitic helminths often evade the immune system by masking and shedding their surface antigens and by varying their antigens during their residence in vertebrate hosts. This ability to mask, shed and vary surface antigens is a primary cause of the difficulty experienced heretofore in producing efficacious vaccines against helminths infection. A review of modern vaccines used in the treatment of parasitic diseases is provided in, J.H.L. Playfair. et al., The Lancet 335 (1990): 1263-1266, while a more general discussion of the nature of the immunological response of hosts to parasitic helminths can be found in the article by S. Lloyd and E. J. L. Soulsby in "Parasitology in Focus: Facts and Trends", Ed. H. Mehlhorn, Springer-Verlag (1988) pp. 619-650. As indicated in the Playfair et al. review article and as mentioned hereinabove, since existing helminth control measures are expensive and difficult to implement on a wide scale, there is a strong need for vaccines capable of reducing the intensity and prevalence of helminth infection in host populations. Prior to the present invention, it was thought unlikely that one antigen alone could confer adequate protection against a wide range of helminth infections based on the difficulties referred to above encountered in producing effective anti-helminth vaccines against even specific species. For an overall review of medical and scientific challenges provided by helminths, see A.A.F. Mahmoud, Science 246 (1989): 1015- 1021. (In addition see also the entries "Parasites, Escape from Immunity", by D.J. Mclaren, and "Parasites, Immunity to" by F.E.G. Cox, in the Encyclopedia of Immunology , eds. I.M. Roitt and P.J. Delves, Academic Press, 1992.) Summary of the Invention In accordance with the present invention, there is provided a compound for protecting a vertebrate against infection by helminths comprising hyaluronidase covalently coupled to an immunostimulating carrier. In preferred form, the compound of the present invention is administered to the vertebrate in the form of a vaccine and the immunostimulating carrier to which the hyaluronidase is covalently coupled comprises copolymers of ethylenepiperazine N-oxide and N-ethylacetylethylenepiperazinium bromide (hereafter referred to as "synpol"). The present invention is based in part on the discovery that the enzyme hyaluronidase is produced by larval helminth species in order to penetrate the tissue barriers in the body of a host organism they have infected. In practice, the present invention is capable of eliciting an immune response against hyaluronidase, as produced by the helminths, thereby drastically reducing, if not eliminating, the ability of the helminths to penetrate tissue barriers and thereby infect an animal. Another aspect of the present invention is the provision of a process for protecting a vertebrate against infection by helminths comprising administration to the vertebrate of a therapeutically effective amount of a compound comprising hyaluronidase covalently coupled to an immunostimulating carrier, preferably synpol. In preferred form, the compound is administered to the vertebrate in the form of a vaccine which includes, in admixture with the compound, synpol. Examples of vertebrates that can be treated in accordance with the present invention include man, cattle, sheep, swine, dogs, horses, cats, goats, buffaloes, camelidae and poultry. An additional aspect of the present invention is the provision of a process comprising reacting hyaluronidase and an immunostimulating carrier under conditions of time and temperature to covalently couple hyaluronidase and said immunogenic carrier. The present invention is believed to offer a variety of advantages over prior art techniques for protecting vertebrates from helminthic infections. The compound of the present invention provides protection against infection by those helminth species which utilize hyaluronidase to facilitate their migration within the body of a host organism. Accordingly, the compound of the present invention is efficient against a broad spectrum of helminth species. This is a significant advantage over prior art vaccines which are often limited to protecting a host from only one specific helminth species. An additional advantage offered by the vaccines of the present invention is that they are strongly immunogenic. Prior art anti-helminth vaccines are often only weakly immunogenic and induce undesirable side effects such as localized inflammation, allergic response, and fever. In addition, prior art vaccines often utilize macromolecular carrier proteins that cause a number of immunopathologic side effects in the vaccinated organism. These and the various other disadvantages of the prior art anti-helminth vaccines have been overcome by the provision of the compound of the present invention inasmuch as it is able to elicit a strong immunogenic response without the side effects often seen in prior art anti-helminthic vaccine preparations. Furthermore, the compounds of the present invention do not appear to effect development or fertility. The ability of the vaccine of the present invention to elicit a strong immunogenic response and to provide a broad spectrum of protection against a variety of helminth species offer advantages heretofore unseen in the art of anti-helminthic vaccines. Brief Description of the Drawings Figure 1 illustrates the general formula for synpol. Figure 2 constitutes the structural formula of synpol which is produced as described in Example 1. Figure 3 constitutes the structural formula of synpol which is produced as described in Example 2. Detailed Description of the Invention One aspect of the present invention is the provision of a material which comprises the reaction product of hyaluronidase and an immunostimulating carrier. Hyaluronidase, as the term is used herein, refers to a family of enzymes which hydrolyze naturally occurring polysaccharides, in particular, hyaluronic acid and glycosaminoglycans such as chondroitin sulfates (4-, 6-, D and E). These polymeric substances are essential components of the semisolid gel-like structure of the extracellular matrix. Hyaluronidase cleaves these polymeric substances and therefore is capable of destroying extracellular matrices. A large variety of helminth species produce and use hyaluronidase to hydrolyze the aforementioned components of the host organism's extracellular matrices thereby permitting the helminths to penetrate tissue barriers and migrate within the body of a host organism until they reach a preferred organ where they grow and mature. The hyaluronidase family includes related enzymes which hydrolyze the aforementioned type substrates. These can be grouped according to their specificity for different linkages within the structure of hyaluronic acid polymer molecules. In particular, the hyaluronidases may be grouped into three primary groups: hyaluronoglucosaminidases, hyaluronoglucuronidases, and glucoronate lyases (B. Fiszer-Szafarz, Analytical Biochemistry, vol. 143, p. 76 (1984)). Native hyaluronidase alone demonstrates extremely weak immunogenicity and does not induce visible anti-hyaluronidase antibody production, even after repeated injections. Hyaluronidase has been isolated from a variety of sources, including snake and bee venoms, leech saliva, the acrosomal granula of spermatozoa, the lysosomal granula of various cells and from bacterial toxins. Exemplary sources of hyaluronidase that can be used in the practice of the present invention include cattle and sheep testes, helminths, leeches, bee and snake venoms and bacteria. Bacterial sources of hyaluronidase include, but are not limited to, the following: Streptococcus millery (P.F. Unsworth, J. Clin. Pathology, (London) 1989, 42(5), 506-510); Streptococcus pyogenes (W.L. Hynes and J.J. Ferretti, Infection and Immunity , 1989, 57(2), 533-539); Streptococcus equisimilis (R. Sting et al., Med. Sci. Res ., 1989, vol. 17, No. 17, pp. 723-725); Clostridium difficicle (S.V. Seddon et al., J. Med. Microbiol ., 1990, v. 31. no. 3, pp. 169-174); Stroptococcus uberis (P. Schaufuss et al., Zentralbl . Bakteriol. FRG, 1989, v. 271, no. 1, pp. 46-53); and Streptococcus dysgalactiae (A. Hamai et al., Agric. Biol. Chem., 1989, v. 53, No. 8, pp. 2163-2168). In addition, yeast of the genus candida have also been found to contain hyaluronidase. M.T. Shimizu, Rev. Microbiol., 1988, v. 19, No. 4, pp. 442-445). In a given species, hyaluronidase generally can be found in monomeric as well as oligomeric forms, with, for example, dimers and tetramers of the same subunit often being present. The amino acid sequence for hyaluronidase produced by streptococcus pyogenes bacteriophage has been determined (W.L. Hynes et al., Infection and Immunity 57 (1989): 533-539) and bee venom hyaluronidase has recently been sequenced (M. Gmachl et al., Proc. Natl. Acad. Sci. USA , 90, 3569-3573 (1993)). It is anticipated that the sequencing and cloning of the genes encoding hyaluronidase will be the basis for recombinant DNA based production of hyaluronidase for use in the practice of the present invention. A variety of commercially-available preparations of hyaluronidase may be used to prepare the compound of the present invention, including, for example, a bovine preparation of hyaluronidase sold by REANAL CO. (Catalog No. 0705). Polyacrylamide gel electrophoresis (PAGE) of the hyaluronidase obtained from this source indicates the presence of a major protein band having an approximate molecular weight of 63 kilodaltons (kDa). There can be used also a material obtained from sheep testes sold by Sigma Chemical Co. (catalog no. H2126). Polyacrylamide gel electrophoresis of the hyaluronidase obtained from this source reveals a major protein band having an approximate molecular weight of approximately 39 kDa. Hyaluronidase may also be obtained from Serva (Catalog No. 25119 and Catalog No. 25121). While the hyaluronidase preparations obtained from various commercial sources differ with regards to the predominate protein species present as evidenced by PAGE, it has been found that the various commercial preparations of hyaluronidase are all enzymatically active and are also immunologically cross-reactive with each other. In addition, practically all preparations investigated contain at least traces of a protein species having a molecular weight of approximately 60-69 kDa and one cannot exclude the possibility that the shorter polypeptide chains present in the reducing conditions used in the PAGE process are assembled under physiological conditions into oligomers of about 60-90 kDa. It is anticipated that compounds of the present invention utilizing hyaluronidase isolated from both ram and bull testes may offer a combination of particularly desirable immunogenicity, cost effectiveness, and convenience. Purification methods for such hyaluronidases are rather well developed and include the commonly used steps of extraction, precipitation, centrifugation, ultrafiltration, ion exchange, and gel chromatography. The compounds of the present invention utilizing hyaluronidase isolated from sheep or bovine testes provoke an immune response to helminth hyaluronidase. Utilization of hyaluronidase isolated from sheep or bovine testes is also significantly more cost-effective than isolating hyaluronidase from helminth larvae. Hyaluronidase of testicular origin has been found to cleave hyaluronic acid and is also able to recognize chondroitin sulfates. (Bartolucci et al., Int. J. Tissue React., 13(6) (1991), p. 311). Accordingly, particularly preferred embodiments of the compounds of the present invention are made utilizing hyaluronidase obtained from the testicles of rams or bulls. In this regard, it has been found that a hyaluronidase of sheep or bovine origin sold by Sigma Chemical Company is suitable in the practice of the present invention. It has been observed that the compounds of the present invention which utilize hyaluronidase obtained from a source other than the animal receiving the treatment of the present invention is often more immunogenic than compounds utilizing hyaluronidase isolated from the species being treated. For example, hyaluronidase isolated from sheep tends to induce a stronger immune response in cattle than hyaluronidase isolated from cattle. For cost effectiveness and convenience in the treatment of sheep and cattle, consideration should be given to use of a compound that is prepared from a mixture of both ram and bull hyaluronidases. Compounds within the scope of the present invention comprise the reaction product of hyaluronidase, as described above, and an immunostimulating carrier. As the term is used herein, "immunostimulating carrier" refers to a compound which, when combined with a given antigen, provides for a highly immunogenic complex (antigen-immunostimulant) which may effectively immunize even low responding individuals to a given antigen. Examples of immunostimulating carriers which can be used in the practice of the present invention are described in the following publication which includes a discussion of the utilization of synthetic polyions as immunostimulators: Khaitov, R., Annals New York Academy of Sciences, 685, 788-802, June 23, 1993. Reference is made in this article to polyoxidonium which is equivalent to Synpol as used in the present invention. In preferred embodiments, the immunostimulating carrier that is reacted with hyaluronidase is synpol. As used herein, the term "synpol" refers to copolymers of ethylenepiperazine N-oxide and N-ethylacetylethylene-piperazinium bromide, corresponding to the formulae shown below in Figure 1, where n = 200-2000; q = (0.2-0.35)n; z = (0.4-0.65)n; m = (0-0.4)n. Synpol, unlike most other carriers and adjuvants, is non-immunogenic. It is thought that synpol has no recognizable antigenic determinants and, accordingly, does not provoke an immune response thereby avoiding undesirable side effects observed with most other adjuvants and carriers used in vaccine preparations. In order to identify in a convenient way the various species of synpol one from another, the term "synpol" is used in combination and sequentially with values for each of the aforementioned letters "n", "q', "z", and "m". For example, ethylenepiperazine N-oxide and N-acetylethylenepiperazinium bromide with n = 1000, q = 0.35, z = 0.60, m = 0.05 is referred to as "synpol 1000-35/60". An example of a specific synpol species copolymer used successfully as an immunostimulating carrier in the vaccine embodiments of the present invention will be referred to herein as "synpol 1000-20/50". Synpol having a molecular weight of at least about 15 kDa or greater is preferred in the practice of the present invention with Synpol having a molecular weight greater than at least about 30 kDa being especially preferred. The compound of the present invention can be made by any suitable method which effects the chemical linking of hyaluronidase to the immunostimulating carrier, for example, by covalently coupling hyaluronidase to the immunostimulating carrier. Such covalent bonds can be formed directly between reactive groups on the hyaluronidase and on the immunostimulating carrier or they can be formed through one or more linking groups. As will be seen in examples set forth hereinbelow, a preferred method for preparing the reaction product of hyaluronidase and the preferred immunostimulating carrier of the present invention, that is, synpol, involves use of the azide method. This method involves converting the acid or ester form of synpol to the hydrazide by use of hydrazine and thereafter combining it with hyaluronidase under conditions which produce a reaction product in which hyaluronidase is covalently coupled to synpol. Alternatively, and as also illustrated in the following examples, another preferred method for preparing the reaction product of hyaluronidase and synpol involves the formation of a succinimide ether or synpol. The succinimide ether is then combined with hyaluronidase under conditions to produce a compound for use in the practice of the present invention. It is believed that the compound of the present invention will be used most widely to protect vertebrates from infection by helminths. For this purpose, it is preferred that the product of the reaction of a hyaluronidase and an immunostimulating carrier be used in the form of a vaccine. As the term is used herein, "vaccine" refers to a composition which contains the compound of the present invention and which is in a form that is capable of being administered to a vertebrate. Typically, the vaccine comprises a conventional saline or buffered aqueous solution medium in which the compound of the present invention is suspended or dissolved. In this form, the compound of the present invention can be used conveniently to prevent, ameliorate, or otherwise treat a helminth infection. In preferred form, the vaccine of the present invention additionally includes an adjuvant which can be present in either a minor or major proportion relative to the compound of the present invention. The term "adjuvant" as used herein refers to non-specific stimulators of the immune response which when combined with the vaccine of the present invention, provide for an enhanced immune response. A variety of adjuvants can be used. Examples include complete and incomplete Freund's adjuvant, aluminum hydroxide, and modified muramyldipeptide. In preferred embodiments of the present invention, synpol is used as an adjuvant in admixture with the compound of the present invention. As mentioned herein above, the compounds of the present invention are intended to be used to protect vertebrates species from helminthic infections. Examples of vertebrates that can be treated in accordance with the present invention include man and various domesticated animals, including, for example, cattle, sheep, swine, dogs, horses, cats, and goats, as well as other equidae, buffalos, camelidae, and poultry. In particular, it is expected that the compounds of the present invention will be efficacious in the prevention and treatment of parasitic helminth infections in animals which are exposed to helminth species which utilize hyaluronidase. The compound of the present invention may he administered parenterally by intramuscular, subcutaneous, or intradermal administration. The preferred route of administration for a given organism may be found by reference to the Examples section of the application. Preferred does ranges may vary given the animal being treated and the most prevalent helminth species in a given environment, but in general, a vaccine dose of about 0.05 mg of protein/kg of animal weight has been found to be effective. Further guidance regarding effective does ranges may be found by referring to the Examples section hereinbelow. It has been found that the mild conditions which can be preferably utilized for covalently coupling hyaluronidase to synpol do not affect the antigenic epitopes of hyaluronidase in a significant manner; accordingly, a highly immunogenic compound is obtained. Solid-phase enzyme-linked immunoassays (ELISA) have shown that anti-hyaluronidase antibodies can recognize the epitopes of hyaluronidase which have been conjugated to synpol, demonstrating that these epitopes are retained. It has been found also that the enzymatic site of hyaluronidase is retained after the covalent coupling of hyaluronidase to synpol. In particular, it has been observed that the substrate degradation rate of hyaluronidase alone is substantially identical to the substrate degradation rate of hyaluronidase which has been covalently coupled to synpol. Furthermore, hyaluronidase when coupled to synpol, is significantly more stable than the native enzyme. This has been demonstrated using hyaluronidase enzyme inactivation tests, including thermostability trials and resistance to heparin mediated inhibition. The enhanced stability of hyaluronidase provided by its conjugation to synpol provides a broad spectrum of other utilities for the compound of the present invention. In addition to its ability to inhibit helminth infections, it is anticipated that the compound of the present invention may be used to elicit an immune response to other pathogens or organisms, for example, those pathogens or organism which make use of hyaluronidase to digest tissue, such as, for example, certain bacteria and their toxins. In addition, the compound of the present invention can be used to block the action or to localize the spreading of venoms containing hyaluronidase (such as bee and snake venoms). The present invention also includes within its scope methods of using hyaluronidase covalently coupled to synpol to treat fibrosis in vertebrates by administering a composition comprising hyaluronidase covalently bound to synpol. In addition, the compound of the present invention can be used in cosmetology as the active ingredient in creams and other products used to make skin smoother and more tender. In this regard, it should be noted that materials containing human sperm have been used as skin-care products in Russia. However, the use of such a product is highly limited because of the instability of the hyaluronidase. Since the compound of the present invention is stable, soluble, and non-toxic, it has immediate applications in this area, and indeed investigations of it uses in this regard have been carried out. The present invention also includes within its scope the use of hyaluronidase covalently bound to synpol as a spreading factor to increase the efficacy of medications. It can also be used to improve diffusion and hasten absorption in medical use, for example, as an ingredient in an antibiotic solution for the treatment of bovine mastitis in veterinary use. In the past, unstabilized hyaluronidase has been used in these contexts (cf. The Merck Index, 8th Edition for example), and accordingly, the stabilized form of hyaluronidase provided by the present invention is expected to provide significant advantages over compositions which use the native form of hyaluronidase. The present invention also includes within its scope the use of hyaluronidase covalently bound to synpol in the following therapeutic contexts where free (unstabilized) hyaluronidase has been shown to have beneficial effects: myocardial infarctions (cf. E.J. Flint et al, The Lancet, April 17 (1982) pp.871-874 and also D. Maclean et al, Science, vol. 194, pp.199-200 (1976)); improving retinal function (cf. B.S. Winkler et al, Arch. Opthalmol . 103 (1985) pp.1743-1746); in combination with cytostatics in the treatment of cancer tumors (G. Baumgartner et al., J. Exp. Clin. Cancer. Res. 4 (1985) p.3, and W. Scheithauer et al., Anticancer Res ., vol 8,pp.391-395 (1988)); in the management of tuberculous spinal arachnoiditis (cf. M. Gourie-Devi et al., J. Neurol. Sci ., vol. 102, pp.105-111 (1991)); for the management of encapsulated brain abscesses in high-risk risk patients (cf. A, Pasaoglu, Acta Neurochir ., vol. 100, pp.79-83 (1989)). Furthermore, hyaluronidase has been used in vitro for depolymerizing hyaluronic acid in a cell free system, for instance, or for stimulating hyaluronic acid synthetase in eg. cell-culturing procedures (L.H. Philipson et al, Biochemistry 24 (1985) pp.7899-7906). The present invention also includes within its scope the use of the compound comprising hyaluronidase covalently bound to synpol in these contexts. In addition, the invention includes within its scope synpol-antigen conjugate vaccines in which the antigen comprises proteins similar to hyaluronidase, for example, vaccines containing as the antigen other enzymes used by pathogens to digest/degrade tissue (including collagenases and proteinases of different specificities). The invention also includes within its scope the use of synpol coupled with an allergen in order to abolish allergic reactions within a host to a given allergen. Extensive investigation has shown that administering such an antigen-synpol conjugate induces preferentially the production of non-allergic antibody isotypes against the allergen in question. These normal non-pathogenic isotypes compete with the previously existing allergenic one (e.g. IgE immunoglobulins) and specifically abolish the allergy. This method of specific desensitization has been clearly demonstrated and is now in the first stage of clinical trials. The invention also includes within its scope the use of synpol coupled with the following antigens to enhance the immunogenicity of the coupled antigens, thereby serving to promote the induction of an effective prophylactic immune response: beta-subunit of cholera toxin, hemagglutinin from envelope of types A and B influenza viruses, p. 90 toxin from B. anthracis, the Vi antigen from salmonella, porin protein from the cell wall of E. coli and salmonellae, synthetic fragments of the gp160 env-protein of HIV-1, F(ab)2 fragments of immunoglobulins (in order to induce an anti-idiotype response). Examples The first two examples are illustrative of the preparation of two species of synpol, as identified in the examples. Example 1 -- Preparation of Synpol 1000-20/50 A three step procedure was used to synthesize a copolymer of ethylenepiperazine N-oxide and N-acetylethylenpiperazinium bromide. (1) The initial polymer, 1,4-ethylenepiperazine, was synthesized in the first step. For this purpose, the living'chain polymerization of 1,4-diazabicyclo[2.2.2]octane was performed according to the following protocol. 10 g of the preliminarily sublimed monomer and 0.05 g of ammonium bromide were sealed in 10 ml glass ampule. A vacuum of residual pressure 5x10 -3 mm Hg was produced in the ampule using a vacuum pump. The ampule was exposed for 25 hours at 200°C in a thermostat. Polymer yield was about 100%, M.W. 120,000 (estimated by LALLS-low angle laser light scattering). (2) The second step was performed to produce the N-oxide of poly-1,4-ethylenepiperazine. 5 g of poly-1,4-ethylenpiperazine (M.W. 120,000, n=1000) were dissolved in 250 ml of 1% acetic acid solution. Then, 4 ml of 30% H 2 O 2 were added, and oxidation lasted for 36 hours. After ultrafiltration and lyophilization, the N-oxide of poly-1,4-ethylenepiperazine (M.W. 110,000, z = 0.5n) was obtained. (3) The alkylation of the above poly-N-oxide was performed during the third step. Poly-1,4-ethylenepiperazine N-oxide produced during the second step was dissolved in 125 ml of methanol and 16.5 g of bromoacetic acid were added. The alkylation reaction was carried out for 10 hrs. at 25°C. The solvent was evaporated in a vacuum and the deposit dissolved in water, dialyzed against water for 24 hrs, and dried using lyophilization. Finally, the copolymer of ethylenepiperazine N-oxide and N-acetylethylenepiperazinium bromide of the following formula was obtained (see Figure 2). The yield was 95%. The oxidation ratio was estimated by the chromometric (or titanometric titration) method and by the ratio of integral intensities of PMR-spectrum bands in region 2.5-4.5 m.d. The chromometric or titanometric titration method refers to the method of quantitative determination of N-oxide groups reduced by salts of bivalent chrome or trivalent titanium (Brooks, R.T. and P.D. Sternglanz, Anal. Chem., 1959, v. 31, N4, p. 561-565). Oxidation ratio amounted to z=0.5n. Alkylation ratio was determined by IR-spectra (1735 cm band) and PMR-spectra (2.5-4.5 m.d. region) and accounted q = 0.2n. Example 2 -- Preparation of Synpol 200-35/65 A copolymer of ethylenepiperazine N-oxide and N-acetylethylenepiperazinium bromide with M.W. 25,000 (n = 200, q = 0.35n, z = 0.65n) was synthesized using a three step procedure, similar to the one of Example 1. (1) In the first step, 10 g of the preliminarily sublimed monomer and 0.11 g of ammonium bromide were sealed in a 10 ml glass ampule. Then a vacuum (5 x 10 -3 mm Hg) was produced in the ampule by a vacuum pump, and the ampule was kept at 200°C for 15 hours. The yield of poly-1,4-ethylenepiperazine was about 100%, M.W. 80,000 (measured by LALLS). (2) In the second step, the N-oxidation of poly-1,4-ethylenepiperazine was carried out as follows. 5 g of poly-1,4-ethylenepiperazine obtained in the first step were dissolved in 250 ml of 1% acetic acid solution. Then 4.6 ml of 30% H 2 O 2 was added at 2-4°C using gentle agitation. The oxidation lasted for 48 hours. Then after ultrafilter cleaning and lyophilization, the N-oxide of poly-1,4-ethylenepiperazine (M.W. 50,000, z = 0.65n) was recovered. (3) The quantity of poly-1,4-ethylenepiperazine N-oxide produced in the step (2) above was dissolved in 125 ml of methanol and then 16.5 g of bromoacetic acid were added. The reaction of alkylation was carried out at 30°C for 24 hours. The solvent was evaporated in a vacuum and the resulting deposit obtained was dissolved in water, dialyzed for 24 hours against water, and lyophilized. There was produced a copolymer of ethylenepiperazine N-oxide and N-acetylethylenepiperazinium bromide having the following formula (see Figure 3). The yield was 95%. The oxidation and alkylation ratio, both estimated as in Example 1, were z = 0.65n and q = 0.35n respectively. The conjugation of synpol to hyaluronidase, and the properties and use of the conjugates, are described in WO-A-95/07100.

Claims: A polymer which is a copolymer of ethylenepiperazine N-oxide and N-(carboxymethyl)ethylene-piperazinium. A polymer having the formula shown in Figure 1. A polymer having the formula shown in Figure 2. A polymer having the formula shown in Figure 3. A polymer according to any of claims 1 to 4, having a molecular weight of at least 15 kD. A polymer according to claim 5, having a molecular weight of at least 30 kD. A polymer according to any of claims 1 to 6, for therapeutic use as an immunostimulating agent. A polymer according to any of claims 1 to 6, for therapeutic use as an immunostimulating adjuvant. A polymer according to any of claims 1 to 6, for therapeutic use as an immunostimulating carrier. The combination of an antigen and a polymer according to any of claims 1 to 6. A conjugate of an antigen and a polymer according to any of claims 1 to 6. A vaccine composition comprising a combination according to claim 10 or a conjugate according to claim 11. Use of a polymer, combination, conjugate or vaccine according to any of claims 1 to 12, for the manufacture of a medicament for use in stimulating the immune response.

Inventors: ATAULLAKHANOV RAVSHAN I, DAUGALIEVEA EMMA K, KHAITOV RAKHIM M, NEKRASOV ARKADY V, PETROV REM V, ATAULLAKHANOV, RAVSHAN I., DAUGALIEVEA, EMMA K., KHAITOV, RAKHIM M., NEKRASOV, ARKADY V., PETROV, REM V.
Applicants: PETROVAX INC, PETROVAX, INC.
Application year: 1994
Main classification: C08G73
IPC codes: C08G73